Keyboard with binary signal generating structure



Jan. 21, 1969 wrrz 3,422,946

KEYBOARD WITH BINARY SIGNAL GENERATING STRUCTURE Filed Aug. 25, 1967 29 32 am, 28 25 m 2L E x m lir' H m 27 25 33 lNVENTOR ,aa/, %/ew/72 ATTYS.

United States Patent US. Cl. 197-16 1 Claim Int. Cl. B41j 23/02, 5/08 ABSTRACT OF THE DISCLOSURE A keyboard of power-driven typewriters for the production of binary signal steps by means of selector slides controllable through actuating keys and acting upon selector flaps by means of an accessory drive mechanism, whereby. after pivoting of the respective selector slide, responsive to actuation of the associated key, into the range of the drive mechanism, the latter acting on the selector slides in thrust direction is released, in which a single member operatively associated with an actuated key and triggered in response to travel of such key is operatively connected with such accessory drive for controlling the subsequent operating sequence in the production of such steps, and in which, according to further features of the invention, means are provided for locking a selected code selector slide in a selected position, whereby the accessory drive mechanism is released only after such locking action, and in which the selector flaps are provided with dead-center springs whereby they flip from a partially pivoted position into final actuated position independently of further movement of the associated selector slide and remain in the final position until reset.

The invention relates to a keyboard for power-operated typewriters for producing binary signal steps through selectorslides controllable by the keys and acting on selector flaps with the use of an accessory drive, whereby after pivoting of the respective selector slide, through actuation of the associated key into the area of the driving mechanism, the drive means affecting the selector slides in the actuating direction is released.

Keyboards of this type are employed in powendriven typewriters employing a single type carrier on which all the type symbols required for the printing operation are arranged, and which must be adjusted by aggregate-motion gearing, and in teleprinters and data-processing machines in which the imprinted symbols must be binary-coded.

Keyboards of known power-driven typewriters usually have the disadvantage that for their operation only such writing forces are suitable consistent with mechanical and operational limitations inherent therein. This circumstance is created, among other things, by the fact that the key impact or touch of different operators are not equal and are not always uniform in the same person. Thus, there is the danger, especially when writing rapidly. that the resulting key travel is insufficient to accurately execute the functions assigned to it.

Essential for a faultless functioning of such a keyboard is the requirement that, first, the selector slides are pivoted,

3,422,946 Patented Jan. 21, 1969 "ice as a result of the key travel ahead of the accessory driving mechanism, and if possible locked in such position, and that only thereafter is the accessory drive released. To achieve a faultless separation of these various operations. the key travel in the known keyboards must be selected sufliciently large. A large key travel, however, adversely affects the operating speed to a great extent.

It is the problem of the present invention to produce a keyboard, wherein the precise succession of the respective operations necessary for symbol imprinting is assured, in particular that, first, the code selector slides are pivoted ahead of the accessory driving mechanism and locked in such position, and that only thereafter is the accessory drive released.

Furthermore, in order to achieve a faultless writing operation, the requirement arises that all the remaining operating sequence of the keyboard functions be controlled through a single criterion achieved by the key travel.

According to the invention, the problem is solved by a keyboard which is characterized by the fact that as a result of the key travel a single member is tripped which controls the remaining operating sequence.

This preferably is achieved in a further development of the keyboard according to the invention. wherein in the pivotal range of each individual selector slide traversed by the key stroke, there is arranged a pawl cooperating with a shoulder on the selector slide and that in the operating range of this pawl a rocker arm which releases the drive is so disposed that upon movement of the pawl into engagement with a pivoted selector slide the trigger rocker arm is actuated to release the drive.

Therefore, in keyboards according to the invention, the accessory driving mechanism is actuated without additional key travel after pivoting of the selector slide. The driving mechanism is actuated not by reason of the key travel itself, but by movement of the latch pawl. Thus, the initial movement of the pawl, which controls the actuation of the accessory driving mechanism and therefore the remaining operating sequence of the keyboard, i the only criterion affected by the key travel.

It is necessary to again disconnect the trigger rocker arm in the course of the actuating movement of the selector slides. Consequently, in a further development of the keyboard according to the invention, each of the pawls, rotatably disposed about a stationary axis, has a projection or nose which during the thrust movement of the selector slide associated therewith, cooperates with a shoulder of such selector slide, whose distance from the axis of rotation of the pawl is less than the distance of the pawl tip from the axis of rotation.

In a preferred embodiment of the keyboard according to the invention, dead-center springs are associated with the selector flaps so that the latter snap from the tilting position achieved by the actuating movement of the selector slide into an adjusted position and, until subsequently reset, remain in this position independently of further movement of the selector slides. Preferably. there is disposed in the range of the selector flaps a connecting rod or member controllable by a cam, through which the selector flap can be reset into their original positions. The cam producing the reset movement of the selector flaps, in this case, is advantageously arranged on the drive shaft producing the actuating movement.

These features assure that the time for evaluating the adjusted position of the selector flaps can be established by corresponding profiling of the reset cam independently of the further movement of the actuated selector slide, the selector slides themselves being returned to their original positions by means of reset springs.

Details of theinvention will be apparent from the illustrative embodiment shown in the drawing, in which:

FIG. 1 is a sectional view through a keyboard, transverse to the axis of the accessory drive and the selector flaps; and

FIG. 2 is a similar section illustrating the principal features of the reset mechanism for the selector flaps.

By actuating a key 1 of the keyboard in opposition to a refir n spring 2, a selector slide 4 is pivoted into a spherical stop 5 by means of a pivot lever 3. After completion of a fixed Stroke of key 1 and, therefore, a predetermined pivotal movement of selector slide 4, latch end or tip 6 of pawl 7 engages the edge 8 disposed on code slide 4, and pawl 7, due to the action of spring 9 rotates counterclockwise, interlocking with such edge and locking the selector slide 4 in actuated position. In addition, through the movement of pawl 7 trigger flap 10 is actuated in a counterclockwise direction. A three-toothed drive shaft 11 is thereby released for a one-third rotation. During this partial rotation, a tooth of the drive shaft 11 engages projection 12 of the interlocked selector slide 4 which has been disposed on the spherical stop 5, pushing such slide to the right as viewed in FIG. 1. Thus, flaps 13 are engaged by such teeth 14, as may be positioned on the selector slides in accordance with the desired coding, and rotated clockwise. In addition, pawl 7 is rotated clockwise by the operating travel of selector slide 4 as a result of engagement of projection 16 with cooperable shoulder 15. Since the distance of pawl tip 6 from rotational axis 17 is greater than the distance of projection 16 from axis 17, the release of the interlock between pawl 7 and selector slide 4 is effected when this movement takes place, before projection 12 leaves the range of the drive shaft. Selector slide 4 is drawn in an upward direction about axis 19 due to the action spring 18, with the shoulder 20 seated against pawl end 6, as a result of which pawl 7 is likewise prevented from moving int-o latching position. Selector slide 4 and pawl 6 thus return to their original positions under the influence of springs 18 and 9. In the event key 1, and consequently pivot lever 3, remain depressed, shoulder 21 of selector slide 4 is positioned ahead of shoulder 22 of pivot lever 3 so that an automatic repetition of the symbol is precluded. For a renewed imprint of the same symbol, key 1 and pivot lever 3 must first assume their original positions.

Due to the fact that prior to the release of selector slide 4 from pawl 7, selector flaps 13 have already passed to tilting position of over-center springs 23 connected to the respective selector flaps 13, the latter will continue to rotate in their tilted position under the influence of the over-center springs 23 which are normally in their least compressed state as indicated in FIG. 1. A lever 24, illustrated in FIG. 2, is attached to the same shaft as the selector flaps 13 and rotates with the flaps under the influence of the over-center springs 23 until the pin or projection 25 on the lever strikes the edge 26 of a slide member 27. The slide member 27 is controlled by a cam 28 secured to the drive shaft 11 by means of a lever 29. After contact between the pin 25 and the edge 26 of the slide 27, rotation of the cam 28 will always impart a forward movement to the edge 26, thereby moving the lever 24. A similar lever 24 is provided for each selector flap 13, only one however, being illustrated in FIGURE 2.

Upon rotation of lever 24, a permanent magnet 30 disposed in the fork thereof likewise slides to the right and actuates a protective gas contact 31. Through the use of over-center springs 23, which can also be replaced by a stop spring or friction brakes, the length of the switching time thereof is independent of the ft Iil s r movement of the actuated selector slide 4. The duration of the contact actuation is terminated by the rising flank 32 of cam 28 which resets slide *27 by means of lever 29 in opposition to a spring 33 and, consequently, also selector flaps 13, by engagement of the edge 26 with pin 25 and actuation of lever 24.

After the drive shaft has rotated through an angle of the shaft is again restricted and the next tooth is thus made available. Hence, a return time of the driving member is not required. The impact velocities between drive and selector slides and between selector slides and selector flap-s are thus relatively small, contributing to the reduction of noise, in addition to the reduction of the driving speed due to the 120 driving angle of the threetoothed drive shaft.

The brief storage of a signal will be described in connection with the illustrative embodiment. This storage becomes necessary if, due to the particular imprint combination by the operator, two keys are depressed so quickly one after another that the keyboard has not fully evaluated the command of the first key before the second key is actuated.

It is known that the simultaneous depression of two keys blocks spherical stop 5, which permits only one selector slide 4 to complete its downward movement. When a selector slide 4 is depressed into the spherical stop, a second depressed selector slide is so positioned upon the spheres that its projection 12 cannot be engaged by the teeth of drive shaft 11. Since the first depressed code slide has released the drive, it is engaged by a tooth of drive shaft 11 and is pushed to the right. During this movement, edge 34 runs out of spherical stop 5 in horizontal direction, and as soon as edge 34 has passed the center of spherical stop 5, the next selector slide thereafter can be depressed and interlocked with pawl 7.

The movements must be so synchronized that upon subsequent depression of the second selector sli-de its projection 12 cannot be engaged by the same tooth of drive shaft 11 which actuated the first code slide. The next release of the drive is introduced by the actuation of the pawl 7 associated with the second selector slide. The drive clutch, and consequently the drive shaft, is not maintained stationary after the initial 120 rotation, but rotates another 120, thus initiating the coding of the second signal.

Changes may be made within the scope and spirit of the appended claim which define what is believed to be new and desired to have protected by Letters Patent.

I claim:

1. A power-driven typewriter binary signal actuating system comprising: driving means, a plurality of typewriter keys and signal actuating means for each key, said signal actuating means including a plurality of selector flaps, a selector slide having a shoulder and being actuatable in a thrust direction to pivot said selector flaps, said selector slide being pivoted from a rest position into an operating position adjacent said driving means by actuation of an associated key, a pivotable pawl associated with said selector slide and having a latch tip adapted to engage said shoulder on said selector slide to retain it in said operating position, said .pawl being pivoted by movement of said selector slide into said operating position, said drive means being actuated in response to the pivoting of said pawl, said drive means being effective to move said selector slide in the said thrust direction, movement of the said selector slide in said thrust direction being effective to disengage said latch tip from said shoulder, means associated with said selector slide to return it to the rest position, said selector flaps being pivotally supported and provided with over center springs operative upon pivotal movement of a selector flap, and responsive to partial movement of the said selector slide in the said thrust direction to flip such flap into its final position independently of further movement of said selector slide and maintain the said selector flap in said final position, a reset slide co-operable with said selector flaps for returning the latter to their original position, and a rotatable cam member operatively connected with said reset slide for actuating said reset slide to reset the said selector flaps.

References Cited UNITED STATES PATENTS Palmer et a1. 19716 Palmer 19716 Barnard et al. 19798 Reynard 197-16 6 3,233,061 2/1966 Jones 19798 XR 3,251,962 5/1966 Jones 19798 XR 3,327,828 6/1967 Dawnatt 197-98 ROBERT E. PULFREY, Primary Examiner.

EDGAR S. BURR, Assistant Examiner.

US. Cl. X.R. 

